Thompson sustained damage to his ribs during Northamptons Premiership defeat by Sale on Saturday and left the field after just eight minutes, with further medical checks revealing he needs at least 14 days on the sidelines to recover.

England host Canada at Twickenham on November 13 and the match could arrive too soon for Thompson, who looked certain to claim the hooking duties despite his ongoing efforts to recover his best form.

He will miss the opening two fixtures of Northamptons European Cup campaign against Glasgow at Hughenden on Sunday and Llanelli six days later.

Even if Thompsons recovery progresses as expected, he will have precious little time to prove his fitness to England boss Andy Robinson who must now be considering the alternatives.

Leeds veteran front rower Mark Regan is the player in possession of the number two jersey after nudging Thompson out of Englands starting line-up for two matches during the summer tour Down Under.

Regan featured in the second Test against New Zealand and faced Australia a week later but his inclusion owed more to Thompsons dramatic post-World Cup slump in form than his own qualities.

A safety-first approach would see Robinson stick with the tried and tested Regan but he may be tempted to give Sale forward Andy Titterrell an opportunity to shine in the least demanding of Englands Autumn internationals.

Titterrell has one cap, coming on as a substitute against the All Blacks last summer, and his athleticism and mobility have won many admirers, although doubts linger over whether he is too small at 58 for the Test arena.

Veteran flanker Richard Hill has already been ruled out of the three-Test series after undergoing reconstructive knee surgery and England can ill-afford to lose any more of their World Cup winners.

Hills absence and the international retirement of Neil Back and Lawrence Dallaglio has left Robinson with a major headache in the back row.

Wasps Joe Worsley and Leicesters Martin Corry are likely to fill two of the slots while Lewis Moody could figure if he impresses upon his return to first team action, which looks set to begin on Saturday when Leicester face Calvisano.

But the lack of a standout openside to fill Backs shoes is a concern. Pat Sanderson of Worcester has been in fine form while Baths Michael Lipman is a possibility, but there are precious few alternatives.

However, Dallaglio - who called time on his glittering Test career at the end of August - believes the abundance of quality English back rowers ensures there is little to worry about.

Lets forget about Hill, Back and Dallaglio and concentrate on whos there. England will always be strong in the back row, he said on Monday.

England dont have any problems in that department - there are guys queuing up for a place.

If you havent got a genuine openside then you have to perm things slightly differently and England have enough options to do that.

The midfield is another problem area and Robinson has seen his options reduced by the news that Smith will be out for a minimum of four weeks after injuring his shoulder during Leicesters triumph at Harlequins on Saturday.

Smiths loss will be easier for Robinson to bear given the gifted Tigers back was unlikely to make the starting line-up, though his ability to cover centre and wing may have won him a spot on the bench.